The present invention relates to machines, such as cranes, which have an upper works rotatably mounted on a lower works. In particular, the present invention provides a locking mechanism to prevent the upper works from rotating relative to the lower works.
Machines of this type utilize a swing bearing to permit rotation of the upper works relative to the lower works. It may be necessary, however, to prevent the rotation of the upper works during certain lifting operations. It may also be necessary to prevent the rotation of the upper works when the machine has been shut down. For example, a crane having a large boom has a tendency to swing with the wind when not in use, which may result in injury or damage to nearby structures.
Known machines of this type typically employ a locking device connected directly to the swing bearing. Such devices often require the upper works to be carefully aligned with the lower works before engaging the device. It is therefore desirable to provide a swing lock mechanism which can be easily engaged.